The aim of this study was to determine the individual and combined toxic effects of STOMP 330 EC herbicide (33% pendimethalin) and copper sulphate on the development of chicken embryos. On the first day of incubation chicken eggs were dipped in the solution or emulsion of the test materials for 30 minutes. Applied concentration of copper sulphate was 0.01% and of herbicide STOMP 330 EC was 1.25%. The chicken embryos were examined for the followings: rate of embryo mortality, body weight, type of developmental anomalies, macroscopic examination. Our teratogenicity study revealed that, the individual toxic effect of copper sulphate and pendimethalin containing herbicide formulation (STOMP 330 EC) were embryotoxic but not teratogenic in chicken. The combined administration of STOMP 330 EC and copper sulphate did not increase the embryotoxic effect.